<!DOCTYPE HTML>
<title>Fonts and margins of HTML headers</title>
<style type="text/css">

div { border: medium solid blue }

</style>

<div><h1>Level 1</h1></div>
<article>
<div><h1>Level 2</h1></div>
<nav>
<div><h1>Level 3</h1></div>
</nav>
<section>
<aside>
<div><h1>Level 4</h1></div>
</aside>
</section>
<section>
<nav>
<nav>
<div><h1>Level 5</h1></div>
<aside>
<div><h1>Level 6</h1></div>
</aside>
</nav>
</nav>
</section>
</article>
